US2542732A - Device for conversion of frequencies - Google Patents

Description

Feb. 20, 1951 E. ToRcHEUx 2,542,732

DEVICE FOR CONVERSON'OF FREQUENCIES Filed May 3, 1945 7 Sheets-Sheet 1 DEVICE FOR CONVERSION OF FREQUENCIES Filed May 5, 1945 7 Sheets-Sheet 2 I l A@ e 'la D l @I UO S, So

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INVENTOR ENTS b. 20, 1951 E. ToRcHEux 2,542,732

DEVICE FOR CONVERSION OF FREQUENCIES Filed May 3, 1945 x 7 Sheets-Sheet 3 @mai/MMM.

ATTORNEYS Feb. 20, 1951 E. ToRcHEUx DEVICE FOR CONVERSION oF -FREQUENCIES 'r sheets-sheet 4 Filed May 3, 1945 In v Mq, 2, 95% E. TORCHEUX I DEVICE FOR CONVERSION 0F FREQUENCIES Filed may 5 1945 'smets-snt s www? BMCKE BMC/m wat@ @Lma @lam 27am; 9am .vom mad 15d i MMM @ma Kc. afan/fc. fwn/Ya. i 'Hanke 250m;

K w 50 /fc Arrows/fm' Feb@ 2, w51 E. "mmm-umm DEVICE FOR CONVERSION OF FREQUENCIES Filed may 5, 1945 7 S'aezS-Sheet` 6 mmf/vra@ EM/.f 75m/750% Afro/wim' Filed May 3, 1945 E. TECH-MIEUX DEVICE FOR CONVERSION 0F FREQUENGIES '7 Sheets-Sheet 7 Patented Feb. 20, 1.951

DEVICE FOR CONVERSION OF FREQUENCIES Emile Torcheux, Paris, France, assignor to Societe Franaise Radio Electrique, a corporation of France Application May 3, 1945, Serial No. 591,714 In France January 26, 1940 Section 1, Public Law 690, August 8, 1946 Patent expires January 26. 1960 (Cl. Z50- 40) 4 Claims.

This invention relates to devices for conversion of frequencies such as those used in the transmission or reception of radio-electric waves.

The construction of transmitting and receiving 2 range of frequencies F1.` The device acts on the well known principle of the change of frequency and makesuse of members and devices known per se as hereinafter indicated, the invention apparatus capable of operating on any frequen- 5 consisting essentially of the combination of three cies over their entire range under conditions of elements as follows: great Stability and precision of adjustment f l. At least one frequency changer selector comthe wave transmitted or received is of great inprising, es known per Se, et least one lter ee,- terest not only with respect to the reliability of pabie of being tuned to the frequencies F1 by a the communication but also as t0 the quality 0f l0 tuning system with linear variation of frequency. reception and rapidity of establishing a connec- 2. At least one generator to produce, in a mantion. These conditions are of particular impclner known per se, at least two substitutable fixed tance in communications in which the Wave frequencies Fq selected in such a manner that lengths used are frequently changed and where it in the frequency changer the equation: is desired to tune to a predetermined Wavelength l5 and establish immediate contact with the best |F1"F 1l=F possible ratio 0f signal t0 parasitic ncise- In can be satisfied by using one of the frequencies this connection it may be remarked that an ap- Fn whatever may be the value of F1 under conparatus as visualised in the present invention sideyetien must be capable of being regulated in advance on 3. A system of connection ensuring a demulto a given WaVelength and be capable 0f at Once tiplication of movement between the member receiving an emiSSicn having this Wavelength; controlling the tuning system on the frequencies the recepticn must take Place under the best Fo and the member controlling the tuning sysconditions of the ratio between useful signal tem on the frequencies F1, in such a manner t0 parasite noises, that is to say, the receiver 25 that there corresponds to every variation of fremust be eXactly regulated t0 the Wavelength t0 quency on the frequencies Fo the same variation be received. in absolute value on the frequencies F1, the said In most cases. the precision and Stability are system of connection comprising furthermore a eXDressed as a percentage 0f the frequency transdisplacement device effective to modify, indemitted. Means are knOWn fOr Obtaining Very pendently of the movement of the member conereat stability in the Case 0f a particular fretrouing the tuning syste-rn on the frequencies F0 (luency 0r in the Vicinity of this frequency, but and conjointly with the placing in service of the there is then excluded the possibility of Varying fixed frequency Fq utilised in the change of frethe frequency over a continuous and extended quency, the member controlling the tuning sysrange. 35 tem on the frequencies F1 to a position of ad- Now what it is required to obtain is that with jugement; this movementy defined by the disthe saine Systen 0f COTnInunicatiOn, Whether this placement effected by the member controlling the be in Short Waves 0r Ineclilln WaVeS, the band 0C- tuning system on the frequencies F1 from its inicupied presents the Same absolutJe Value; for eX- tial position (i. e. that from which the frequencies ample, in telephony a Value 0f 6 kcand in teleg- 40 F1 are traversed) to its position of adjustment, raphy a Value limited by the speed 0f manipllbeing such that when the tuning system on the lation. frequencies F1 is tuned to the frequency corre- The device forming the object 0f the Present sponding to the said position of adjustment, the invention enables transmitters and receivers to System of tuning en i-,he frequencies F0 is tuned be produced having the above qualities for any to one of the limit frequencies of the range of frequency within the entire range for which the frequencies Fo. transmitter or receiver is constructed. The invention will now be further described This device applied to a receiver serves to bring with reference to the Figure la, of the accomthe various frequencies F1 of an extended range panying drawings, in which the device according into closer limits of a lower range of frequencies to the invention is represented diagrammatically F0 covered in a continuous manner by a tuning as applied by Way of example to a receiver and system with linear variation of frequency; apas comprising only one frequency changer stage. plied to a transmitter, it serves on the contrary In such a device it is a question of bringing the to bring the various frequencies F0 of a restricted frequencies F1 of a Wide range extending from range into more extended limits of a higher F10 to F11 into the narrower limits F00, F01 of a lower range of frequencies Fo covered in a continuous manner by a tuning system with linear variation of frequency. This tuning system, represented by Co, has for its object to select the frequency Fo in the frequency selector So, and it is controlled by an actuating member Un the displacement ao of which is connected to the frequency Fo by the linear rule:

in which K and o are constants.

The device comprises in combination, in accordance with the foregoing general statement of invention:

1. A frequency changer selector (S1-M 1) comprising at least one lter adapted to be tuned on the frequencies F1 by a tuning system with linear variation of frequency. This tuning system, represented by C1 on Figure la, is controlled by a controlling member U1 the displacement a1 of which is connected to the frequency F1 by the linear rule:

in which K1 and 181 are constants.

2. A generator G producing at least two substitutable fixed frequencies. These fixed frequencies, any one of which will be indicated by Fq, are selected in such a manner that in the frequency changer M1 the equation:

|F1-Fl=Fo (3) may be satisfied by using one of the frequencies Fq, whatever may be the value of F1 under consideration.

The Equation 3 may be set out in the following algebraical form:

F1-Fq=eF0 (3') by assuming that:

e=+1when F1 F 1 and e=l when F1 F I (4) The xed frequencies will be obtained, for example, by means of one or more quartz oscillators in order to ensure a great stability of frequency.

3. A system of connection Lensuring a demultiplication of movement as between the control member Un of the tuning system Co and the control member U1 of the tuning system C1, in such a manner that there corresponds to every variation of frequency on the frequencies Fo the same variation in absolue value on the frequencies F1.

It is thus necessary to have:

dF1=edFo (5) The value of E is given by the Equation 4 since the Equation 3 must be satisfied at the same time as Equation 5.

Let us indicate by m the ratio of demultiplication between the respective displacements dan and dm of U0 and U1, there is given:

da1=m.dao (6) From the Equations 1, 2, 5 and 6, there is deduced 4the value of m' as follows:

The system of connection L comprises, intel' alia, a displacement device D effective to modify 'the adjustment of U1 independently of the movement of Un. This adjustment is dened by the displacement necessary to cause a1 to pass from its vinitial value 111 corresponding to the initial frequency F1' from which the range of frequencies F1 is passed through, to its adjustment value a1Y to which the frequency F17 corresponds. There is thus obtained by definition of the ad- J'ustment: l

Y 0l1nl 0l10 with, according to the Equation 2,

Taking this equation into consideration (8) becomes:

and

in which according to the invention, F0 is equal to one of the limit frequencies of the range of frequencies Fo, that is to say either to F00 or F01. This relation permits of determining ry as soon as the direction has been fixed in which the frequencies F1 are passed through. If, for example, the direction is of increasing frequencies, on the one hand F1=F1U and on the other hand if the lower limit F00 be taken for For, the frequencies Fo can only increase, that is to say, there is given: e=ll according to the Equation (5): on the contrary, if the upper limit F01 is taken for Fol, the frequencies Fo can only decrease that is to say, there is given: e=-l. There are consequently only two possible solutions, for with The device according to the invention permits of obtaining simultaneously the precise tuning of the two selectors So and S1 at the same time that it permits of covering extensive ranges with very few electric contacts, due to the fact that the passage from one section of frequencies to the following one takes place by changing the zone used of the control member of the tuning system. This reduction in the number of the electric contacts is still further accentuated when there are placed in cascade several similar devices. On the other hand, the device is particularly well adapted for the use of the two frequencies which can be obtained in the change of frequency (these two frequencies are given by the Equation 3 according to the Value of e) In this case, it is obviously necessary to provide means for reversing the ratio of demultiplication between the members U0 and U1. These means may consist of mechanical devices such as connecting rods or eccentrics or electrical devices such as condensers with two symmetrical stators with commutation or a set of two similar condensers of connected and reversed movement, with commutation.

The system of connection is carried out by means of a train of gearing with differential movement permitting, by displacement of the crown wheel of the gear carrying the satellites, of shifting the control member U1 with respect to the control member Uu without modifying the ratio of demultiplication between these two members.

An advantageous arrangement is realisable when the range of frequencies F covers the frequencies f to 3f (f being a definite number of kilocycles) and the range of frequencies F1 covers the frequencies from 3f to 91. Thus in this case, with two xed frequencies only, equal respectively to f and 7j, all the frequencies F1 can be brought into the range of frequencies Fo by using as the connecting system a system of gearing with diflierential movement having a ratio of 1/3 and comprising four positions of adjustment.

In general, the range to be transposed is very extended, it is then transposed by successive stages by the aid of devices similar to that decribed, placed in cascade. In this the ranges to be transposed is decomposed into intermediate ranges of decreasing extent in such a manner as to terminate finally at the range of frequencies Fo. It is later on indicated, by way of example, how it is possible to rise from the range of frequencies Fo to a range of frequencies Fn of any rank by employing the decomposition termed with base 3. In case of the reception, the frequencies Fo varying from f to 3f arise from a first frequency change selector receiving the frequencies F1 variable from 3f to 9j and operating with two substitutable xed frequencies 5f and 7j, the frequencies F1 arising themselves from a second frequency changer selector receiving the frequencies F2 variable from 321 to 3(2+1)f and operating with two substitutable xed frequencies 5 S(21 f and 7 3 21)f, the frequencies F2 from a third frequency changer selector receiving the frequencies F3 variable from 33 to 3 3+Uf and operating with two substitutable fixed frequencies 5 3 3Uf and 7 3 31)j, and so on, the frequencies F11-1 variable from 311-11 to 3f"1+1f arising from an nth frequency changer selector receiving the frequencies Fn variable from Suf to 3 11+Uf and operating with two substitutable fixed frequencies 5 3f11f and 7 3n1f.

The base 3 is particularly advantageous because on the one hand it allows the simplification of the mechanism and on the other it ensures protection against image waves, against the waves having the value of the frequencies resulting from the successive transpositions and against the reinjection of the heterodyne in the aerial.

Other distributions of the intermediate ranges are, however, possible. For example, the frequencies F0 still extending from f to 3f, the rst frequency changer selector covers the frequencies from 4f to 12j and operates with two fixed frequencies 'if and 91, the second frequency changer selector covers the frequencies from 161 to 48j and operates with two fixed frequencies 28j and 35j, the third frequency changer selector covers the frequencies from 64] to 192f and operates with the fixed frequencies 112 and 144i, and so on.

It would also be possible to start from a different range F0 extending, for example, from 2f to 4f. There might then be used a first selector covering the frequencies from 12j to 24f and operating with the substitutable fixed frequencies l6f, 181e and 20j, a second frequency changer selector covering the frequencies from 72j to 144i and operating with the substitutable fixed frequencies 96j, 108f and 1201, and so on.

When the receiver operates on the heterodyne principle, the frequencies Fo are themselves made to beat with the variable frequency of the heterodyne, according to known practice. Where the frequencies F0 extend from j to 3j, there is used a heterodyne giving the frequencies from 3 /2f to 5/21, in such a manner as to bring all the frequencies F0 to the frequency f/2 of the stage of mean frequency.

By placing in service successively all the frequency changer selectors, it would be possible to successively cover the range of frequencies F1, the range of frequencies F2, the range of frequencies Fs, etc. As the frequencies F0 can also be received directly, it will be seen that there can be covered in this way a very extended range starting from the smallest value of Fo and extending up to the greatest value of Fn.

An indicator device of the frequency Fn, on which the apparatus is regulated, is actuated on the one hand, from the shaft U (see Figure 1a) ensuring the simultaneous drive of the driving members U0 U1, U2 U11 and on the other hand, from the section handle T (or combiner) operating conjointly the regulation of the displacement device or devices and the placing into service of the fixed frequency or frequencies.

By reason of the linearity of frequency of the tuning systems, the indicator device indicates in a general way angles proportional to the frequencies. It may, therefore, take the form of a revolution counter the unit column of which is driven from the tuning knob (controlling the shaft U) and the hundreds or tens column by the combiner, if necessary through the intermediary of a system of differential gears. The possibility is thus given of obtaining directly the indication of the frequency in kilocycles and covering the whole range dealt with by the aid of two means of control only, the tuning knob and the combiner. Y

Naturally, the device applies equally to emission as to reception, it is sucient, according to known practice, to change the direction of amplification and to consider as transmitted wave, the wave previously considered as received wave.

There will now be described, with reference to the accompanying drawings and by way of example only, one method of carrying out the abovedescribed system, and in the description of this method, there will be indicated various constructional forms for certain of the members or elements entering into the constitution of the system.

In the drawings referred to,

Figure 1 shows the wiring schematic of part of a receiver according to the invention.

Figure la shows a simplified diagram of the essential parts of the embodiment of the invention.

Fig. 2 is a perspective view of part of the operating mechanism indicated diagrammatically in Fig. 1;

Figs. 3 and 4 are diagrammatic side elevations of parts of Fig. 2 in different operative positions;

Fig. 5 shows a general view of the mechanism of one embodiment of the invention;

Figs. 6 and 7 show diagrammatically how to divide and operate an embodiment of the invention shown by way of example;

Figs. 8 and 9 show in perspective and partly diagrammatically some further mechanical details and associated wiring schematics; and

Fig. 10 shows a perspective view of a coordinating mechanism for operating a device according to the'invention.

The receiver according. to the invention shown in Fig. l comprises the following elements:

(i) A first filter changer block I of range comprised between the limits 250-75() kilocycles, having two pre-selector circuits '2 and 3, an amplifier valve a tuned circuit y and a mixer Valve 6;

(ii) A heterodyne 'I of range 375-625 kilocycles, as stable as possible in comparison with the temperature and controlled mechanically with precision; this heterodyne excites the modulator electrode of the valve B of the preceding block, in suchY manner that at the outlet of this block there is collected a xed frequency or very stable mean frequency of 125 kc.;

(iii) A mean frequency block 8 comprising (a) a narrow pass-band filter 9 regulated to allow the passage simply of the frequency 125 kilocycles and the immediately adjacent frequencies with variable selectivity and (b) a mean frequency amplier with two valves I and a beat mixer valve II;

(iv) A mean frequency heterodyne I2 of 127 kilocycles, and

(V) An anti-fading detector block I3 and low frequency amplier.

This combination of elements, acted upon by an aerial I G, in the first position of a commutator I5, ensures the reception of the rst sub-range comprising the frequencies from 250 to 750 kilocycles.

A second sub-range of 750 to 2500 kilocycles is received by the addition to the preceding elements of:

A second filter-changer block I6 comprising two pre-selector circuits I'I and I8, an amplifier valve I9, two circuits 20 and a mixer valve 2I A heterodyne 22 of the two xed frequencies 1250 and 1750 kilocycles produced by quartz oscillators, with a commutator 23, for placing into operation the one or the other frequency.

The total extent of the range, from 250 to 2500 kilocycles, is divided into 9 equal sections, each extending-over 250 kilocycles as shown in the table below, the said table supplying in a general way the essential indications as to the positions and the manipulations of the members (adjustment of the condensers of selector circuits and heterodyne, direction of rotation ofthe said condensers, quartz oscillator used on the heterodyne) corresponding to each of the said sections.

8, different arrangements characteristic of the system. Thus, for the section 250-500 the first high frequency block is utilised in the extent of this sub-range, the displacement or adjustment of the '1 condensers of the selector circuits is zero, the direction of the said condensers is forward, the direction of rotation of the condenser of the'heterodyne associated with the first block (heterodyne 1) is also forward, the second high frequency block isnot in operation and the position of the' aerial commutator I5 is suchthat the aerial is tapped at the inlet terminals of the rst high frequency block.

In the case of the section 50G-750, there are the same arrangements except that the zoner of utilisationof the rst block HF" is that of 500 to' 750 kilocycles, the filter condensers being displaced by 90;

For thev section '750-1000l the lst block HF is utilised in its 250-500 range (traversed in the descending direction-500-250) the filter condensers being displaced by 90", their direction of rotation, as also that of the heterodyne condenser, being in the reverse sense, the 2nd block HF is utilised in its range 750-1000, the filter condensers input of the 1st block HF.

The data of the table, for the other sections, will be self-evident in the light of the above explanations. l

The manipulation of the different members is ensured by means of two handles, one controlling in integral rotation (single control) the movement of the unit drum of the indicator-counter of the frequency and the movement of the condensers of heterodyne l and of the filter changer blocks I i0 and I6, theother, the displacements of the heterodyne condensers and blocks, the reversals of running of the condensers, the quartz oscillator and aerial commutators, the numeral drums of the frequency indicator-counter and all manipulations appertaining to the passage from one section to another. Of these handles, the first has a continuous movement and theY second has an interrupted movement and can fix itself on nine different positionsv (one per section).

Direction table'per section lst block HF 250-750 kc. 2nd block HF 750-2500 kc.

Wage re- D. H t y A Y Tapylnliing oil ceive range is- Dire@ e Displce Direc aeria ena Range ptllaecleg tion 325i-:025 Range ment tion Qtz.

250-500 250-500 0 For. For. lst lter. 500-750 G-750 90 750-l,000 50G-250 90 Rev Rev 7501,000 2nd ltcr. l 000-1, 200 750-500 0 1, 000-1, 250 1, 250-1, 500 50G-250 90 1, 250-l, 500 1 500-1, 750 250-500 0 For. For.' 1, 50G-1, 750 l '1250-2,000 500-750 90 1,750-2,000 2, 000-2, 250 250-500 0 2, OOO-2, 250 2, 250-2, 500.. 500-750 90 2, 250-2, 500

Of the above values, (l) is controlled by the members of the lst differential, (2) and (3) are controlled by the members of the direction reverser, (4) is controlled by the members-of the 2nd differential, (5) is controlled by the members of the quartz reverser and (6) is controlled by the members of the aerial tapping.

The two categories of controls to which respectively the twofhandlesare allocated, are indicated in a general way on Figure l, the rst by dotted Detailed examination of the above table shows ferential at the rate of two and a half revolutions per section; secondly, acts on the adjustment of the condensers of the lst and 2nd lter changer block effected by the single control, according to the above table, these adjustments being effected by the displacement of the connecting members of the differentials 25 and 25; thirdly, actuates the direction reversers of the condensers of the filter changer blocks I and I5; fourthly, actuates the reversers of the quartz oscillator of the heterodyne 22; and fifthly manipulates the aerial commutator I5.

These multiple operations are ensured by the intermediary of a drum selector, illustrated in Figure 2.

As shown in this gure, the selector comprises a drum 38 provided with indentations of different depths or widths into which penetrate the noses of a number of levers or pawls 3 I, 32, 33, 34. Each of these levers actuates a rod system 35, 38, 31,

38. The rod systems 35, 36 act on the differentials 25, 2G to effect the adjustment of the variable condensers of the filters. The rod systems 31, 38 cause the movement of the aerial commutation members, of the quartz oscillators and of the reversal of the lter condensers.

' tion of the drum 38 towards its new position. The

lever 43 also drives a rod system 45, the function of which is to lock the adjustable members of the diiferentials when they have been brought into their approximate position by the rod systems 35, 36.

Furthermore, by means of a retarding member (which may for example, be of the clockwork or dash-pot type) the pawl 44 is kept for a suitable time in the set position, after the return of the cam 42. This permits of avoiding the manipulation of the members for all the intermediate positions between two non-adjacent sections.

Thus, when the section is changed, the manipulations are as follows: 1st, the unlocking of the differentials; 2nd, setting of the levers cr pawls; 3rd, rotation of the drum; 4th, freeing of the pawls; 5th, locking of the differentials.

Figures 3 and 4 show in plan View the position of the parts shown in Figure 2 in the phase of rotation of the drum (Figure 3) and in the phase of operation of the receiver (Figure 4) Figure 5 illustrates a conventional representation of the entirety of the elements 01" the mechanical controls of the system.

Figure 5 shows the selector drum 38 operated through the spindle 39 by the Maltese cross 40, the cam 42, the pawls or catches 3|, the lever 45 and the rod or pawl 44. Connected to the locking rod system 45 are a retarding device 45 constituted by a dash-pot, a resetting spring 47, locking pieces 48, 49 constituted by levers hinged at one of their extremities to the rod 45 and carrying at the other extremity rollers 59, 5I engaging in notches 52, 53, 54, 55 on the adjustable elements of the differentials 28, 25, through the intermediary of which are driven the variable condensers 58, 53 of the lters of the frequency selectorchanger blocks I and I5.

The lever or pawl 3I is connected to the rod 35, which in turn operates, through a toothed sector 60, the displacement of the differential 25 driving the variable condensers 59 of the rst lter changer block I. A re-setting spring 5I draws the lever or pawl towards the drum. A similar operating movement is constituted by the rod 36, actuated by the lever or pawl 32 (not shown in Figure 5), which operates through the differential 25 and a sector 62 and against the action of a spring 63, the displacement manipulation of the condensers 58 of the second lter changer block I6.

The commutation rod system 3T effects either the reversal of direction of rotation or the reversal of variation of the capacities for the same direction of rotation of the variable condensers of the heterodyne I and of the lter block I. This result is obtained by the play of two commutators 64 and 65 putting into operation one or the other of two symmetrical stators with which these condensers are provided. A spring 68 draws the rod 31 back to starting position.

By means of a similar mechanism the rod 38 actuates the commuator 23 of the quartz oscillators Q1 and Q2 of the heterodyne 22 and the rod 81 the commutator I5 of the aerial I4.

There will now be described the detail of the connections operating the continuous movement control. The spindle 68 of this control, upon which is keyed a handwheel 69, drives by a helicoidal worm 'I an intermediate spindle II which, by means of a tangent worm 12, drives the spindle 'I3 of a variable condenser I4 of the heterodyne 1. There is also keyed on the spindle 58 a pinion 'I5 which, through a train of toothed wheels 16, 11, 18, drives the elements of the differentials 2B, 25 with which there are integral in rotation the filter condensers 58, 59.

The spindle 7l, through the gears 18', 11', 18', drives the drum I9 (unit drum) of a drum counter 80. To obtain a transmission without play, the intermediate gear I'I is applied against the other gears by means of a compensator spring 88.

The ratios of reduction of these different controls are as follows: for a half turn of the variable condenser 14 of the heterodyne 1, the condensers 59 of the first filter changer block I rotate by 1/4 of a revolution, those of the second block I6 rotate by 1/14 of a revolution and the drum 'I9 of the units of the frequency indicatorcounter rotates by 25 revolutions.

The ratio of reduction between the movement of the condensers 59 and 58 as also the angles of fixation of the latter condenser, may be easily deduced from the general formulae given at the beginning of the description.

Actually, the condenser 58 is supposed to cover in one-half revolution the frequencies from '750 kc. to 2500 kc. There is thus obtained: for

and for a1=rr F10=2500 These two particular values applied to the Equation 2 give for k1 the Value:

a0=1r Fo1=750 whence according to the Equation l the ratio of reduction m given for the Formula '7 is thus:

ko (l0) For the third line:

'For the fourth and fth lines:

In the counter 30, between the drum 8| of the tens and the drum 19 of the units, there is interposed, in addition to the normal connection mechanism from drum to drum according to the counter or meter system, a connection through a differential 82, permitting of eifecting a displacement corresponding to two and a half revolutions for each change of section (corresponding to 250 Vkilcocycles). The displacement of the differential 82, starting with the movement of the primary spindle 3S of the interrupted control, is transmitted by spindles 83, 84 vand toothed wheels 85,

, 86 and 87.

As regards the heterodyne block I, all useful constructional precautions should be taken to ensure its accuracy; in particular the variable condenser, the self-inductance and the bulb of the oscillator valve, should or may be mounted in a copper box forming an hermetic seal, which box itself may be mounted on the front panel of the receiver. To ensure the greatest possible constancy with reference to the temperature, the -variable condenser should or may be constructed of metal, the coeicient of expansion of which varies very little as a function of the temperature. Even then, the frequency is not rendered entirely independent of temperature; there is still a separation, which, however, can be reduced by about 70% by using condensers having a negative temperature coefficient, which annuls the separation in the centre of the range in question. In place 0f such compensation, there may be utilised two bimetallic strips r89, 9D as reading index, one of these strips being utilised for running in one direction and the other for running in the opposite direction.

The means employed to obtain the reversal of the relative direction of variation of the capacity vof the condensers (that is to say, the condensers of the precision heterodyne l and condensers of the lter i) for the same direction of rotation of the rotors, consists in utilising condensers of the type with two symmetrical stators, placed in use alternately and automatically by the action of the commutators 65, 64.

These condensers are, furthermore, of `a type with linear variation of frequency; preferably, there will be provided for the condenser 0f the precision heterodyne 1, the kind of condenser of this type in which the desired linear law of variation results from the prole of the blades, and for the condensers of the filter l, those of the kind in which the desired linear law is obtained by the interposing of a cam of suitable prole between the actuating spindle and the spindle of the rotor of the said condenser. This system permits of obtaining, with the desired linear law, a more extended ratio between the maximum frequency and the minimum frequency, an extension necessitated by the development of range of the filter I.

While the basic principles of the invention in its widest scope have been clearly set forth in the preceding description, it remains to describe briefly, as illustrated in Figures 6-10, certain arrangements which will aid in understanding the application of the invention to a very wide range of frequencies and which will enable an easier manipulation of the control in the Wide system, which latter' can make use of servo-motors.

The invention may be carried into effect in various ways.

One embodiment will be hereinafter described, by way of non-restrictive example, as applied to the construction of a receiver, said embodiment including numerical values in order that the example may be fully illustrative.

In a general way, in apparatuses of the type in question in this invention, the reading of the frequency takes place on a cyclometer counter, the total range of the apparatus being divided into sections, each covering the same number of kilocycles, and a direct variation of frequency of the resonant circuits being maintained proportionately to the variation of position of the control member.

The frequency is determined by means of two manipulations. The first enables the selection of the section containing the frequency to be received; it actuates the elements of the counter indicating the number of hundreds of kilocycles and a set of combining members which prepares the necessary combinations. The latter are executed when the selected section is engaged.

The second manipulation serves to travel over the section; it therefore controls the variable frequency Aheterodyne of the last change of frequency and operates, in the counter, the wheels of the tens and of the units.

Assume a total range of from 100 to 24,300 kilocycles, this range being divided into sections of 100 kc.

The high frequency portion comprises (Figure 6) ve blocks I, II, III, IV, V of identical design, differing only by their range of frequency. They are used in progression according to the frequency to be received.

For the lowest frequencies (100-300 kc.) only 13 block I is used; this block in conjunction with a variable heterodyne I-I supplies to the amplifier MF the oscillations having a mean frequency of 50 kc., which supply the amplifier detector BF; for higher frequencies (300-900 kc.) blocks I and II are utilised.

The block II transposes the frequency which it receives by utilising quartz oscillators and delivers under these conditions at its output, when the signal frequency varies, a variable intermediate frequency which covers the range of the block I.

The receiver then behaves as a receiver with double frequency change, the first mean frequency servo-motor |06 and it is integral with a contact disc formed in two parts |01, |01 with a slot |08 between the parts. Brushes |09, |09', |09" etc., bear on the contact disc. The motor is supplied with electric current from a source ||0 (Figure 9b), indicated by its two poles iand The terminals of the motor are connected respectively to the brushes |09" and |09"", and, through resistances III, H2, to one of the poles of the source H0. The other pole of the source HU is connected to the brushes |09, |09 and |09 through contacts H3, H3', and H3, of the section combine. The making of one of these contacts, for example the .contact H3, causes of which is variable and the second is fixed. the setting in rotation of the motor in the de- For still higher frequencies (900-2700 kc.) sired direction, the rotation of the motorcontinublock III comes into operation and, by the same ing until the slot |08 comes opposite the brush procedure, supplies a variable intermediate fre- |09. At this moment, the motor stops, the crown quency covering the range of the block II. The having undergone a displacement equal to the receiver is then of triple frequency change. angular distance between the brushes |09', |09". The reception of still higher frequencies neces- The closing of the contact I3 would have caused sitates the placing into service of supplementary the placing in rotation of the motor in the opblocks IV, V, in the example shown. posite direction until the arrival of the slot |08 The following table shows the ranges correopposite the brush |09. sponding to the placing in series of the different There is thus obtained, by a simple electrical blocks: control, the displacement of the differentials, the

Table Wave to be received No. of

Intake from High frequency sections aerial blocks used of 100 kc. F., kcs. Meters 10o- 300 aoco-1,000 Block I 2 c- 900 1,000- 333 mock n-.. e 900- 2,700 a33- 111 mock 111. is 2,700- s,1oc 111- 37 Blockiv-- 54 s, 10o-24, 30o 37- 12.4 Block v-.. 162

Each high frequency block comprises three tuned cicuits of variable frequency covering` a range of ratio 3, an amplifier valve and a mixer valve.

The following component members are utilized.

1. Reduction and adjustment The condensers of direct variation of frequency are controlled from a single manipulation (manipulation of the variable heterodyne condenser) in such a manner that the condensers appertaining to a block of higher index move three times as slow as the condensers of the block of lower index immediately adjacent.

On the other hand, according to the sub-range selected, the adjustment of the condensers of one block with respect to those of the block immediately adjacent must have a well defined value. v

These two conditions are obtained by differentials, which are inserted between the controls of the dilerent blocks according to the diagrammatic arrangement of Figure '77, which is self-explanatory. The adjustment takes place by putting into a definite yposition the satellite-carrying crown of the differential. According to the present invention, this operation is carried out by a small servo-motor rotating automatically just the amount necessary to bring the crown to the desired adjustment, see Fig. 9.

The said mechanism comprises a differential lill, having a reduction ratio of 1:3, coupling the shaft |02 of the lower block with the shaft |03 of the upper block, the crown of the differential being marked |04 and the satellites carried thereon |05. The crown |04 is in engagement with a manipulation of the section combiner being limited to effecting contacts, with consequent elimination of the mechanical eiorts necessitated by a direct control.

2. Reversal of direction To obtain maximum efficiency in the use of the apparatus, it is necessary to utilise in the successive changes of frequency, sometimes the upper beat and sometimes the lov/er beat. It is thus necessary that the variation of the capacity of certain blocks should be an increase for certain sections and a decrease for others. This result is obtained by providing, on each block, not simply a single set of condensers but two sets controlled in opposite directions and by selecting, according to the section, that one of the two which is suitable.

Such an arrangement is obtained, according to the present invention, in the manner shown in Figure 8, the part (a) of which illustrates the mechanism employed and the part (D) the electrical diagram. The mechanism referred to comprises two condensers |253, |2|, which may for example, be of the type having sliding armatures, in which case they have three sets of armatures. The armatures o1' these condensers are controlled by cams W2, |23. The cams Iii?, |23 are keyed on to the shaft mechanically connecting the differential of the block N to which the condensers in question appertain, to the differential of the block immediately above (N+1). r`iheir profile is so chosen that the variation of frequency is in direct relation to the rotation of the shaft, The cams are reversed one with respect to the other in order to obtain the reversal of the law of variation. The operation in forward or in reverse di- 15 rection results, as shown by Figure 8o from the position of the switche 226;, |24', |24" appertaining respectively to the sets of armatures, these switches being connected by the section combiner.

3. Frequency of conversion The value of the frequency utilised for the conversion is one or the other of two fixed values given by quartz oscillators, the frequency of which has or has not been multiplied.

In the present example, the carrying out of the range necessitates eight quartz oscillators, arranged two for each block and distributed according to the following table:

Table No. of the block II III IV V Kc. Kc. Kc. Kc. Frequency of lst quartz oscillatolz." 500 1,500 4, 500 13, :TO Frequency of 2d quartz 0scillator 700 2, l0() 6, 30|) 18, 9U() These dilferent frequencies may be obtained from the two quartz oscillators of 500 and 700 kc. respectively by several times tripling the frequency: if need be, a single quarts oscillator of 1GO kc. may be started with. The latter arrangement permits of the maximum of precision over the whole range.

Only block uses the frequency of a continuous range heterodyne H of ratio 5:3 and the two beats of which are taken; it constitutes the high frequency part of the normal receiver.

4. Combiner As has been remarked with respect to the con-` trol of the variable condensers, the combiners of each block are controlled by a single manipulation by the section-changing handle which directly actuates the counter, in such a manner that the combiner allocated to a block of higher index changes three times less than the preceding combiner.

This condition is carried out, according to the present invention, by Maltese crosses of ratio 3 which are inserted between the controls of the combiners of the different blocks. Figure shows the general operation of the combiners. The section handle |3 directly operates the spindle of the switches allocated to the block I. These switches are distributed in four series, shown diagrammatically in the form of four discs |3|, |32, |33, |34 with three positions of contact. These discs insure respectively the four functions enumerated above under (a) to (d). Other discs may be provided, either to subdivide the operations or to insure supplementary operations allocated to each block. Through the intermediary of the Maltese cross connection |35, |36, the spindle of the switches of the block I drives the spindle of the switches of the block II in such a manner that for one revolution of the first spindle, the second is shifted by a third of a revolution, and so on from one spindle to the next. The method of operation fromv the section handle of the counter drums has not been shown. There may tbe used to this end, the embodiment described hereinbefore. There may also be used a servo-motor drive of the type used in the arrangement of Figure 9. The same type of control could, furthermore, be used in place of Maltese cross systems in the connections between the spindles of the switches of blocks I to V thus eliminating any motive effort to be supplied by the section handle |36.

The remainder of the receiver comprises (see Fig. 6) the usual elements of an amplifier, mean frequency filter MF on 50 kc., low frequency BF, and supply R.

What I claim is:

l. Apparatus for the interconversion of frequencies between two ranges thereof, one being an extended range including higher frequencies (F1) and the other being a fraction of the first mentioned range and including lower frequencies (Fo) comprising oscillator means having a commutator, for the generation of at least two fixed frequencies (Fq), so chosen that there can be a transformation, by combination with one of the fixed frequencies with each frequency of one range, of each frequency of a range into a frequency of the other range, means including commutators for effecting tuning on each section corresponding to a portion of the range of higher frequencies, means including commutators for tuning on the range of lower frequencies, means for effecting coupling between the first mentioned and second mentioned tuning means and the commutator of said oscillator producing the said fixed frequencies, said coupling means being constructed and arranged so that the said higher and lower frequency ranges are each covered in its totality and in a continuous manner by one or more tuning devices variable linearly with frequency, said coupling between tuning devices for the lower and the higher frequencies comprising demultiplication means, whereby under control of the tuning devices the frequencies tuned in the higher and lower frequency ranges are changed by a like absolute value, and an adjusting means which on passing to another section of the range of the higher frequencies enables the adjustment by a predetermined amount of the tuning means for the higher `frequency range relative to that of the lower range.

2. Apparatus according to claim l wherein the said adjusting means comprises a differential device having central planetary wheels and a cage carrying cooperating satellites, the said central planetary wheels being connected respectively to the tuning devices of the lower and higher frequency ranges and including means for effecting changeover to the different sections of high frequency range, said changeover means controlling said cage.

3. Apparatus according to claim 1 including a control device having a continuous movement for controlling simultaneously the tuning device of the lower and higher frequency ranges, a controlling device having a discontinuous movement and having a distinct position for each section of the high frequency range and comprising a number of levers, a drum with intermittent rotary movement for controlling the position of said levers, means by which one lever controls the adjusting means, a second lever switches the REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date Lear Dec. 21, 1937 Lowell Jan. 16, 1940 Banfield Sept. 24, 1940 Carlson June 10, 1941 Brandholt Sept. 29, 1942 Gendriess Feb. 16, 1943 Swallow Jan. 2, 1945 Dimmer June 26, 1945

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